JP6116575B2 - mechanical seal - Google Patents

Description

  The present invention relates to a mechanical seal used as a shaft seal device such as a pump.

  Conventionally, as a kind of mechanical seal, as shown in FIG. 7, it is an inside type of a type that seals the sealed fluid on the high-pressure fluid side that tends to leak from the outer periphery of the sliding surface toward the inner peripheral direction, An annular rotary side slide provided on the rotary shaft 50 for driving a pump impeller (not shown) on the high pressure fluid side via a sleeve 51 and a cup gasket 52 so as to be rotatable integrally with the rotary shaft 50. The ring 53 and an annular fixed side slide ring 55 provided via a bellows 57 in the cartridge 56 in a non-rotating state and axially movable in the pump housing 54 are a fixed side slide ring. It is known that a coiled wave spring 58 and a bellows 57 that bias 55 in the axial direction slide closely between sliding surfaces S that are mirror-finished by lapping or the like. The bellows 57 in this conventional mechanical seal is made of rubber, and one end of the bellows 57 is attached to the stationary ring 55 via a case 59. The other end is attached to the cartridge inner cylinder portion 56 a via a driving band 60.

  Further, in Patent Document 2, as shown in FIG. 8, a stationary sliding ring 62 is attached to a housing 61, and a rotational sliding ring 63 is provided on a shaft rotatably supported by the housing 61. In a mechanical seal in which the sliding ring 62 and the rotating side sliding ring 63 are slidably elastically contacted with each other, the metal bellows 64 is supported by the metal bellows 64 so that the stationary side sliding ring 62 is axially movable. An invention is disclosed in which a fixed claw 64a is formed at the right end of the metal bellows, the fixed claw 64a is bent to support the fixed side sliding ring 62 inside the right end of the metal bellows 64, and the left end of the metal bellows 64 is directly fixed to the housing 61. (Hereinafter referred to as “Prior Art 2”, see Patent Document 2).

  However, since the bellows 57 is made of rubber, the conventional technique 1 has problems such as deterioration and breakage of the bent portion. Further, an urging member such as the coiled wave spring 58 and an attachment member such as the driving band 60 are necessary, and there is a problem that the number of parts increases.

  In the prior art 2, the metal bellows 64 is directly fixed to the housing 61 in such a manner that the fixing ring 62 is directly supported by the metal bellows 64 and the metal bellows 64 also serves as a cartridge. There is a problem that the spring constant of the metal bellows 64 is increased because the metal bellows 64 must have the same thickness.

JP 2000-74226 A (page 3, FIG. 2) Japanese Patent No. 2956862 (page 5, FIG. 5)

The present invention has been made to solve the problems of the prior art, and is a mechanical seal that does not deteriorate or break the bellows, and that reduces the bellows spring constant to reduce the load fluctuation caused by the expansion and contraction of the bellows. It is intended to provide.
Furthermore, normally, in the assembly by integrating the rotating side and the fixed side, it is necessary to increase the inner diameter of the bellows to ensure space, and the pressure receiving area of the bellows changes and the balance value also fluctuates. In some cases, an object of the present invention is to provide a mechanical seal in which fluctuations in the balance value are suppressed.

In order to achieve the above object, a mechanical seal of the present invention first comprises a sleeve fixed to a rotating shaft and a cartridge fixed to a housing, and the sleeve is provided with a rotating side sliding ring, An inside-type mechanical seal in which a cartridge is provided with a fixed-side sliding ring that slides facing the rotation-side sliding ring and a bellows that urges the fixed-side sliding ring in the axial direction. The metal bellows has one end fixed to the case holding the fixed sliding ring and the other end fixed to the cartridge, and the plate thickness is greater than the plate thickness of the case or the cartridge. It is characterized by being set thin.
According to this feature, the metal bellows exclusively plays a role of urging the fixed-side sliding ring in the axial direction, and is formed separately from the case and the cartridge, so the thickness of the metal bellows can be reduced. The spring constant of the metal bellows can be reduced, and the change in load relative to the amount of expansion and contraction of the metal bellows can be reduced. For this reason, even if the rotating side sliding ring fluctuates in the axial direction, the axial biasing force against the fixed side sliding ring can be stabilized, and the pressure of the sliding surface can be maintained at an optimum value. . Moreover, the tolerance of the mounting length of the metal bellows can be relaxed. Furthermore, if a metal bellows is used instead of the conventional rubber bellows, the bellows is not deteriorated or broken, and the life can be increased. Further, compared to the case of the rubber bellows, it is possible to reduce the number of parts for mounting. Furthermore, the spring constant of the bellows can be freely set according to the material, the plate thickness, or the number of peaks. Furthermore, the balance value can be set to an optimum value.

The mechanical seal of the present invention is secondly characterized in that, in the first feature, the metal bellows has a bellows portion in which peaks and troughs are alternately and repeatedly formed at both ends of the bellows portion. A disk-like flange portion extending radially outward from the valley portion, the outer diameter of the flange portion being larger than the diameter of the peak portion, and the inner diameter of the flange portion being substantially the same as or slightly the diameter of the valley portion It is characterized by being formed by molding or welding so as to be large.
According to this feature, the metal bellows can be easily fixed to the case and the cartridge, and leakage of the sealed fluid can be prevented.

Thirdly, in the first or second feature of the mechanical seal according to the present invention, the metal bellows, the metal case, and the metal cartridge are fixed with the flange of the metal bellows. It is characterized by being performed by welding or welding at a position slightly inside the outer diameter of the part.
According to this feature, the inner peripheral portion of the flange portion of the metal bellows can be separated from the case and the cartridge, and has excellent followability with respect to eccentricity of the rotating shaft, and exhibits stable sealing performance. It becomes possible. In addition, the metal bellows can be securely fixed without using a special mounting member.

According to a fourth aspect of the mechanical seal of the present invention, in any one of the first to third features, the rotating side sliding ring is fixed to the sleeve via a cup gasket, and the cup gasket is connected to the rotating side. It is characterized by being provided across the anti-sliding surface side and the outer peripheral surface of the sliding ring.
According to this feature, even when the pressure of the high-pressure fluid acts on the outer peripheral surface of the cup gasket, it is possible to prevent the cup gasket from being detached.

The mechanical seal of the present invention fifthly includes a sleeve fixed to the rotating shaft and a cartridge fixed to the housing, and the sleeve is provided with a rotation-side sliding ring, and the cartridge has the above-mentioned In an inside-type mechanical seal provided with a fixed-side sliding ring that slides facing the rotation-side sliding ring and a bellows that urges the fixed-side sliding ring in the axial direction, the bellows is made of metal. The metal bellows has one end fitted to a gasket that holds the fixed sliding ring, the other end is fixed to the cartridge, and the plate thickness is set to be thinner than the plate thickness of the cartridge. It is characterized by.
According to this feature, since the metal bellows is formed so as to also serve as a case, the number of parts can be reduced and the number of welding points can be reduced.

In addition, the mechanical seal of the present invention is characterized in that, in the sixth feature, a band is attached to the outer periphery of the outer cylindrical portion of the metal bellows that fits into the gasket that holds the fixed sliding ring. It is characterized by being.
According to this feature, the fitting between the metal bellows and the cup gasket can be ensured.

Seventhly, the mechanical seal of the present invention includes a sleeve fixed to the rotation shaft and a cartridge fixed to the housing, and the sleeve is provided with a rotation-side sliding ring. In an inside-type mechanical seal provided with a fixed-side sliding ring that slides facing the rotation-side sliding ring and a bellows that urges the fixed-side sliding ring in the axial direction, the bellows is made of metal. The metal bellows is characterized in that one end is directly fixed to the fixed-side sliding ring, the other end is fixed to the cartridge, and the plate thickness is set to be thinner than the plate thickness of the cartridge. .
According to this feature, the number of parts can be reduced and the axial length of the mechanical seal can be shortened. Further, instead of shortening the axial length of the mechanical seal, the number of metal bellows can be increased.

Eighth, according to any one of the first to seventh features, the mechanical seal of the present invention is engaged with the inner cylinder portion of the cartridge with the tip of the inner cylinder portion of the sleeve being enlarged by caulking. Thus, in the type in which the cartridge and the sleeve are prevented from being detached in the axial direction, the inner cylindrical portion of the cartridge has a diameter-enlarged portion positioned on the side opposite to the fixed sliding ring side in the axial direction. The bellows has an inner diameter of a portion located on the fixed sliding ring side from the step of the inner cylindrical portion of the cartridge, and is opposite to the fixed sliding ring from the step of the inner cylindrical portion of the cartridge. It is characterized by being formed to have a smaller diameter than the inner diameter of the portion located at.
According to this feature, the decrease in the balance value can be suppressed without increasing the outer diameter of the bellows, the amount of leakage on the sliding surface can be reduced, and the increase in the spring constant of the bellows can be suppressed. can do. Furthermore, even when the balance value is set to exceed 100%, it is possible to suppress an increase in diameter of the rotating side sliding ring and the stationary side sliding ring, and to avoid an increase in the size of the mechanical seal. .

The present invention has the following excellent effects.
(1) The bellows is made of metal, and one end of the metal bellows is fixed to the case holding the stationary side sliding ring, the other end is fixed to the cartridge, and the plate thickness is thinner than the plate thickness of the case or the cartridge. By being set, the metal bellows exclusively plays the role of urging the fixed side sliding ring in the axial direction and is formed separately from the case and cartridge etc., so the thickness of the metal bellows The spring constant of the metal bellows can be reduced, and the change in load with respect to the amount of expansion and contraction of the metal bellows can be reduced. For this reason, even if the rotating side sliding ring fluctuates in the axial direction, the axial biasing force against the fixed side sliding ring can be stabilized, and the pressure of the sliding surface can be maintained at an optimum value. . Moreover, the tolerance of the mounting length of the metal bellows can be relaxed.
Furthermore, if a metal bellows is used instead of the conventional rubber bellows, the bellows is not deteriorated or broken, and the life can be increased. Further, compared to the case of the rubber bellows, it is possible to reduce the number of parts for mounting. Furthermore, the spring constant of the bellows can be freely set according to the material, the plate thickness, or the number of peaks. Furthermore, the balance value can be set to an optimum value.

(2) The metal bellows includes a bellows portion in which crest portions and trough portions are alternately and repeatedly formed, and disk-shaped flange portions extending radially outward from the trough portions at both ends of the bellows portion, The outer diameter of the flange portion is larger than the diameter of the peak portion, and the inner diameter of the flange portion is formed by molding or welding so as to be substantially the same as or slightly larger than the valley portion. The bellows can be easily fixed to the case and the cartridge and leakage of the sealed fluid can be prevented.

(3) The metal bellows, the metal case and the metal cartridge are fixed by welding or welding at a position slightly inside the outer diameter of the flange portion of the metal bellows. The inner peripheral part of the flange part of the metal bellows can be separated from the case and the cartridge, and can follow the eccentricity of the rotating shaft, exhibit a stable sealing performance. . In addition, the metal bellows can be securely fixed without using a special mounting member.

(4) The rotation-side sliding ring is fixed to the sleeve via a cup gasket, and the cup gasket is provided across the anti-sliding surface side and the outer peripheral surface of the rotation-side sliding ring, so that the pressure of the high-pressure fluid is reduced to the cup. Even if it acts on the outer peripheral surface of the gasket, the separation of the cup gasket can be prevented.

(5) The metal bellows is formed so that one end of the metal bellows is fitted to a gasket that holds the stationary-side sliding ring and the other end is fixed to the cartridge, so that the metal bellows also serves as a case. Therefore, the number of parts can be reduced, and the number of welding points can be reduced.

(6) A band is attached to the outer periphery of the outer part of the metal bellows that fits into the gasket that holds the fixed sliding ring, so that the metal bellows and the cup gasket can be securely fitted. Can be.

(7) One end of the metal bellows is directly fixed to the fixed sliding ring and the other end is fixed to the cartridge, so that the number of parts can be reduced and the axial length of the mechanical seal can be shortened. . Further, instead of shortening the length of the mechanical seal in the axial direction, the number of metal bellows can be increased.

(8) In the type in which the distal end of the inner cylindrical portion of the sleeve is expanded by caulking and engaged with the inner cylindrical portion of the cartridge, thereby preventing the cartridge and the sleeve from being detached in the axial direction. The inner cylindrical portion has a stepped portion with an enlarged diameter located at a portion opposite to the fixed sliding ring side in the axial direction, and the bellows extends from the stepped portion of the inner cylindrical portion of the cartridge to the fixed side sliding. The inner diameter of the portion located on the moving ring side is formed smaller than the inner diameter of the portion located on the opposite side of the fixed sliding ring from the step of the inner cylinder portion of the cartridge, thereby increasing the outer diameter of the bellows. Therefore, a decrease in the balance value can be suppressed, the amount of leakage on the sliding surface can be reduced, and an increase in the spring constant of the bellows can be suppressed. Furthermore, even when the balance value is set to exceed 100%, it is possible to suppress an increase in diameter of the rotating side sliding ring and the stationary side sliding ring, and to avoid an increase in the size of the mechanical seal. .

It is a longitudinal cross-sectional view which shows the principal part of the mechanical seal which concerns on Example 1 of this invention. It is a longitudinal cross-sectional view which shows the principal part of the mechanical seal which concerns on Example 2 of this invention. It is a longitudinal cross-sectional view which shows the principal part of the mechanical seal which concerns on Example 3 of this invention. It is a longitudinal cross-sectional view which shows the principal part of the mechanical seal which concerns on Example 4 of this invention. It is a longitudinal cross-sectional view which shows the principal part of the mechanical seal which concerns on Example 5 of this invention. It is a longitudinal cross-sectional view which shows the principal part of the mechanical seal which concerns on Example 6 of this invention. It is a longitudinal cross-sectional view which shows the principal part of the mechanical seal of the prior art 1. It is a longitudinal cross-sectional view which shows the principal part of the mechanical seal of the prior art 2. It is a principal part longitudinal cross-sectional view which shows the reference example for demonstrating the mechanical seal which concerns on Example 5 and 6 of this invention.

  EMBODIMENT OF THE INVENTION With reference to drawings, the form for implementing this invention is demonstrated illustratively based on an Example below. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to be limited to them unless otherwise specified.

With reference to FIG. 1, the mechanical seal which concerns on Example 1 of this invention is demonstrated.
The present invention is applied to an inside-type mechanical seal that seals a fluid that leaks from the outer periphery to the inner periphery of the sliding surface, and the left side of FIG. Side (sealed fluid side), right side is low-pressure fluid side (atmosphere side).

  The mechanical seal of the present invention includes a sleeve 2 fixed to the rotary shaft 1 and a cartridge 4 fixed to the housing 3. The sleeve 2 is provided with a rotation side sliding ring 5, and the cartridge 4 has a rotation side. In the mechanical seal provided with the fixed side sliding ring 6 that slides facing the sliding ring 5 and the bellows 7 that urges the fixed side sliding ring 6 in the axial direction, the bellows 7 is made of metal, One end of the metal bellows 7 is fixed to the case 8 that holds the stationary sliding ring 6, the other end is fixed to the cartridge 4, and the plate thickness is set to be thinner than the plate thickness of the case 8 or the cartridge 4. Is the main feature.

   For example, a pump impeller (not shown) is fixed to the high pressure fluid side of the rotary shaft 1, and the mechanical seal of the present invention is provided at the shaft seal portion between the inner diameter side of the pump housing 3 and the outer diameter side of the rotary shaft 1. Is arranged and sealed.

  The sleeve 2 includes an inner cylinder portion 2a fitted to the rotary shaft 1, a disk portion 2b extending in the outer diameter direction from the high-pressure fluid side of the inner cylinder portion 2a, and extending from the outer diameter side of the disk portion 2b to the low-pressure fluid side. An outer cylinder portion 2c is provided, and the rotating side sliding ring 5 is held via a cup gasket 9 on the low pressure fluid side having a substantially U-shaped cross section. The cup gasket 9 is provided across the anti-sliding surface side and the outer peripheral surface of the rotation-side sliding ring 5. For this reason, even if the pressure of the high-pressure fluid acts on the outer peripheral surface of the cup gasket 9, the cup gasket 9 does not come off.

  The cartridge 4 is made of, for example, metal, and has an outer cylinder portion 4a that is fitted into the inner periphery of the housing 3, a disk portion 4b that extends radially inward from the low-pressure fluid side of the outer cylinder portion 4a, and an inner diameter portion of the disk portion 4b. To the high-pressure fluid side along the rotation axis, and the fixed-side sliding ring 6 can be moved in the axial direction via a metal bellows 7 to the high-pressure fluid side having a substantially U-shaped cross section. Hold on. The cartridge 4 is formed in a cartridge type that is detachable from the housing 3. The plate thickness of the cartridge 4 is, for example, about 0.4 mm when made of metal.

The fixed-side sliding ring 6 is held by the case 8 via the cup gasket 10 on the side opposite to the sliding surface and the outer peripheral surface. The case 8 is made of, for example, metal, has a substantially inverted L-shaped cross section having an outer cylinder portion 8a and a disk portion 8b, and holds the fixed side sliding ring 6 via the cup gasket 10 on the high pressure fluid side. It fixes to the end of the metal bellows 7 in the low pressure fluid side of the disk part 8b. The plate thickness of the case 8 is about 0.4 mm when made of metal.
The cup gaskets 9 and 10 can be elastically deformed, and are selected from, for example, rubber, resin, or metal.

  One end of the metal bellows 7 is fixed to the disk portion 8b of the metal case 8 holding the stationary sliding ring 6, and the other end is fixed to the disk portion 4b of the metal cartridge 4 by means such as welding. Is done. That is, the metal bellows 7 is formed separately from the case 8 and the cartridge 4.

In the bellows 7 provided with a telescopic bellows portion in which the peak portions 7a and the valley portions 7b are alternately and repeatedly formed, disk-shaped flange portions 7c extending from the valley portions 7b of the bellows 7 are provided at both axial ends of the bellows 7. The inner diameters of the flange portions 7c and 7c at both ends are substantially the same as or slightly larger than the valley portions 7b of the bellows 7, and the outer diameter of the flange portion 7c is larger than the peak portion 7a of the bellows 7. Has been.
The flange portions 7 c and 7 c at both ends of the bellows 7 are fixed to the disc portion 8 b of the case 8 and the disc portion 4 b of the cartridge 4. When fixed, the case 8 and the cartridge 4 are welded or welded at a position 11 slightly inside the outer diameter of the flange 7c formed larger than the outer diameter of the peak 7a of the bellows 7. Thereby, the bellows 7 can be easily fixed to the case 8 and the cartridge 4 and the sealed fluid can be prevented from leaking.
Further, the disk portion 8b of the case 8 extends slightly to the inner diameter side than the flange portion 7c of the bellows 7, and supports the flange portion 7c of the bellows 7 as a whole, thereby enabling the operation of the bellows 7 and the spring. Constant stability is achieved and the sealing performance is maintained.
Further, since welding is performed only on the inner diameter side slightly from the outer diameter of the flange portion 7 c of the bellows 7, the inner peripheral portion of the flange portion 7 c of the bellows 7 is the disk portion 8 b of the case 8 and the disk portion 4 b of the cartridge 4. It is possible to move away from the center of the rotating shaft 1, and it is excellent in followability with respect to the eccentricity of the rotating shaft 1, and can exhibit a stable sealing property.

  As a material for the metal bellows 7, for example, SUS304, SUS316L, AM350, and Inconel 625 are generally used. The metal bellows 7 is formed of, for example, a molded bellows formed by molding or a welded bellows formed by welding. Further, the plate thickness of the metal bellows 7 is set to be thinner than the plate thickness of the metal case 8 or the metal cartridge 4. For example, the plate thickness of the metal bellows 7 is set to about 0.1 mm, and is formed to be considerably thinner than the plate thickness of the case 8 or the cartridge 4.

  When the plate | board thickness of metal bellows 7 is made thin, the spring constant of the bellows 7 will become small and the change of the load with respect to the expansion-contraction amount of the bellows 7 will also become small. Thus, when the change in load with respect to the expansion / contraction amount of the bellows 7 is reduced, the urging force in the axial direction with respect to the fixed sliding ring 6 is stabilized even if the rotational sliding ring 5 fluctuates in the axial direction. The pressure on the moving surface can be maintained at an optimum value. Further, there is an advantage that the tolerance of the mounting length of the bellows 7 can be relaxed. In the case of FIG. 1, the number of peaks of the metal bellows 7 is two, but when the load on the expansion / contraction amount of the bellows 7 is reduced, it is three, and when the length in the axial direction is shortened, it is 1 The number of mountains may be increased or decreased as necessary, such as a mountain.

Regarding the positional relationship between the effective diameter of the metal bellows 7 (substantially, the center diameter of the inner diameter and the outer diameter) and the radial direction of the sliding surface S, the force that presses the fixed-side sliding ring 6 toward the sliding surface. It is set so that F1 and the force F2 pressing toward the anti-sliding surface are balanced in a fixed relationship.
In the case of the embodiment shown in FIG. 1, the pressure receiving area received from the sealed fluid of the metal bellows 7 (the bellows 7 for acting in the direction of pressing the fixed side sliding ring 6 against the sliding surface side is from the sealed fluid. It is the meaning of the pressure receiving area and is expressed by the area between the effective diameter of the bellows 7 and the outer diameter of the sliding surface S. Hereinafter, the same) is assumed to be A1, and the rotating side sliding ring 5 and the fixed side sliding. When the sliding area with the ring 6 is A2, the balance value represented by the ratio of A1 / A2 is set in the range of 50% ≦ balance value ≦ 100%. The balance value can be changed depending on the setting of the balance diameter (effective diameter) and the sliding area, and is usually set large when the pressure of the sealed fluid is high and small when the pressure is low.

  When a metal bellows is used in place of the conventional rubber bellows, the bellows is not deteriorated or broken, and the life can be increased. Further, compared to the case of the rubber bellows, it is possible to reduce the number of parts for mounting. Furthermore, the spring constant of the bellows can be freely set according to the material, the plate thickness, or the number of peaks. Furthermore, the balance value can be set to an optimum value.

Next, with reference to FIG. 2, the mechanical seal which concerns on Example 2 of this invention is demonstrated.
The second embodiment shown in FIG. 2 is different from the first embodiment shown in FIG. 1 in that a metal bellows is formed so as to also serve as a case, but the other configurations are the same as the first embodiment. Yes, duplicate explanation is omitted.

  In FIG. 2, the metal bellows 15 includes a stretchable bellows portion in which a peak portion 15 a and a valley portion 15 b are alternately repeated, and the bellows 15 has axially opposite end portions from the valley portion 15 b of the bellows 15. An extending disc-shaped flange portion 15 c is provided, and the inner diameters of the flange portions 15 c and 15 c at both ends are formed to be substantially the same as or slightly larger than the valley portion 15 b of the bellows 15, and the outer diameter of the flange portion 15 c is the bellows 15. It is formed larger than the mountain portion 15a. The flange portion 15 c on the cartridge 4 side of the bellows 15 is fixed to the disk portion 4 b of the cartridge 4. An outer cylindrical portion 15d is continuously formed on the flange portion 15c on the fixed sliding ring 6 side so as to be fitted to the outer peripheral surface of the cup gasket 10 that holds the fixed sliding ring 6. 15d and the outer peripheral surface of the cup gasket 10 are elastically fitted. When the flange portion 15c on the cartridge 4 side is fixed to the disk portion 4b of the cartridge 4, a position 11 slightly on the inner diameter side than the outer diameter of the flange portion 15c formed larger than the outer diameter of the peak portion 15a of the bellows 15. In FIG. 4, the cartridge 4 is welded or welded. Thereby, the bellows 15 can be easily fixed to the cartridge 4 and the cup gasket 10 and the sealed fluid can be prevented from leaking. Further, the flange portion 7c on the cartridge 4 side of the bellows 15 is welded only on the inner diameter side slightly from the outer diameter, and the flange portion 15c on the fixed side sliding ring 6 side is elastically attached to the side surface of the cup gasket 10. Therefore, the inner peripheral portion of the flange portion 15c of the bellows 15 can be separated from the side surface of the disc portion 4b of the cartridge 4 and the cup gasket 10, and also follows the eccentricity of the rotary shaft 1. It is possible to exhibit a stable sealing property.

  The material and the forming method of the metal bellows 15 are the same as those of the metal bellows 7 of the first embodiment. The plate thickness of the metal bellows 15 is set to be thinner than the plate thickness of the metal cartridge 4.

  In the second embodiment, since the metal bellows 15 is formed so as to also serve as a case, the number of parts can be reduced and the number of welding points can be reduced.

Next, with reference to FIG. 3, the mechanical seal which concerns on Example 3 of this invention is demonstrated.
The third embodiment shown in FIG. 3 is different from the second embodiment shown in FIG. 2 in that a band is attached to the outer periphery of the outer cylindrical portion of the metal bellows, but the other configuration is the same as the second embodiment. Therefore, a duplicate description is omitted.

  In FIG. 3, a band 16 is attached to the outer periphery of the outer cylinder portion 15 d of the metal bellows 15. The band 16 is configured to fasten the outer cylindrical portion 15d radially inward against the elastic force of the cup gasket 10 radially outward. Examples of the band 16 include a hose band type which is made of an elastically deformable ring-shaped thin plate and has a diameter reduced by tightening a circumferential joint with a screw, or an elastically deformable ring shape. 1 in the circumferential direction of a plate clip type (one-touch phos clamp) that can be operated in the diameter expansion direction with one touch against the force of elastic deformation in the shrinking direction, or a ring-shaped thin plate that can be elastically deformed It is composed of a C-ring type or the like with portions cut off.

  In the third embodiment, the outer cylinder portion 15d of the bellows 15 is fitted to the cup gasket 10 in order to tighten the outer cylinder portion 15d radially inward against the elastic force of the cup gasket 10 radially outward by the band 16. The match can be ensured.

Next, with reference to FIG. 4, the mechanical seal which concerns on Example 4 of this invention is demonstrated.
The fourth embodiment shown in FIG. 4 is different from the first embodiment shown in FIG. 1 in that the flange portion of the metal bellows and the fixed-side sliding ring are directly fixed. This is the same as 1 and redundant description is omitted.

When the fixed sliding ring 6 is made of a metal-weldable material, the metal bellows 7 can be directly welded to the fixed sliding ring 6 without using the case 8 and the cup gasket 10 shown in FIG.
In FIG. 4, the flange portions 7 c and 7 c at both ends of the bellows 7 are fixed to the disk portion 4 b of the cartridge 4 and the anti-sliding surface side 6 a of the fixed side sliding ring 6. When being fixed, the fixed side sliding ring 6 and the cartridge 4 are directly connected to the fixed side sliding ring 6 and the cartridge 4 at a position 11 slightly on the inner diameter side than the outer diameter of the flange portion 7c formed larger than the outer diameter of the peak portion 7a of the bellows 7. Welded or welded.
Examples of the material of the stationary-side sliding ring 6 include stainless steel (SUS304), sintered metal, cemented carbide, or silicon carbide (SiC). When the material of the stationary side sliding ring 6 is stainless steel (SUS304) and sintered metal, it can be fixed by welding, and when it is cemented carbide and silicon carbide (SiC), it can be fixed by brazing.

  In the fourth embodiment, since the case 8 and the cup gasket 10 as shown in FIG. 1 are not used, the number of parts can be reduced, and the axial length of the mechanical seal can be shortened. In addition, the number of peaks of the metal bellows 7 can be increased instead of shortening the axial length of the mechanical seal.

Next, with reference to FIG.5 and FIG.9, the mechanical seal which concerns on Example 5 of this invention is demonstrated.
The fifth embodiment shown in FIG. 5 is an integrated type by so-called fixed / rotating side caulking, which can prevent the cartridge and sleeve from coming off in the axial direction, and thus the first embodiment shown in FIGS. Although different from the fourth embodiment, other configurations, for example, the balance value is the same as those of the embodiments in that 50% ≦ balance value ≦ 100%, and overlapping description will be given. Omitted.

FIG. 9 is a reference example for explaining the mechanical seal according to the fifth embodiment of the present invention.
In the type in which the distal end 2d of the inner cylindrical portion 2a of the sleeve 2 is expanded by caulking and engaged with the inner cylindrical portion 4c of the cartridge 4 to prevent the cartridge 4 and the sleeve 2 from being detached in the axial direction. The inner cylinder part 4c is provided with a step part 4d that engages with the tip 2d of the inner cylinder part 2a of the sleeve 2. The step portion 4d is formed by increasing the diameter of a part of the inner cylinder portion 4c on the disk portion 4b side, and the inner diameter portion of the sleeve 2 is formed on the enlarged diameter portion of the inner cylinder portion 4c. A distal end 2d having a diameter expanded by caulking of the cylindrical portion 2a is fitted, and the distal end 2d and the stepped portion 4d are engaged with each other.

As shown in FIG. 9, in order to provide the step portion 4d in the inner cylinder portion 4c of the cartridge 4, the inner diameter of the bellows 7 is made larger than the inner diameter of the bellows of Embodiments 1 to 4, and is constant between the inner cylinder portion 4c. It is necessary to provide a gap. When the inner diameter of the bellows 7 is increased, if the outer diameter is constant, the effective diameter increases, and the pressure receiving area A1 received from the sealed fluid of the bellows 7 decreases, so that the balance value = A1 / A2 (A2 is sliding) There is a problem that the area of the surface is reduced and the amount of leakage is increased.
If the outer diameter of the bellows 7 is increased, the pressure receiving area A1 increases and the balance value also increases. However, if the outer diameter of the bellows 7 is increased, welding work between the bellows 7 and metal parts such as the cartridge 4 is performed. This is not practical because it becomes difficult and the outer diameter of the mechanical seal increases.

  The mechanical seal according to Example 5 of the present invention solves the problems of the reference example, and FIG. 5 is a longitudinal sectional view showing the main part thereof. The broken line in FIG. 5 shows a cross section of the rotation preventing portion provided in a part of the fixed-side sliding ring 6 in the circumferential direction, and the solid line shows a cross section of a portion other than the rotation preventing portion. In Examples 1 to 4 of FIGS. 1 to 4, the solid line indicates the rotation preventing part, the broken line indicates the cross section of the part other than the rotation preventing part, and is the reverse of FIG. 5.

  In FIG. 5, the tip 20 d of the inner cylindrical portion 20 a of the sleeve 20 is expanded by caulking to engage with the inner cylindrical portion 40 c of the cartridge 40, thereby preventing the cartridge 40 and the sleeve 20 from separating in the axial direction. A part of the inner cylinder part 40c of the cartridge 40 on the disk part 40b side is enlarged in diameter to form an enlarged diameter part 40e, and a step part 40d is provided. A step portion 40 d that engages with the tip 20 d of the inner tube portion 20 a of the sleeve 20 is provided. By engaging the step 20d of the inner cylindrical portion 40c with the tip 20d of the sleeve 20 which has been enlarged by caulking of the inner cylindrical portion 20a, the axial separation between the cartridge 40 and the sleeve 20 is prevented, and the fixed side And the rotating side are integrated.

The metal bellows 30 has the same outer diameter as that of the above-described reference example, and the inner diameter of the inner cylinder portion of the cartridge 40 is such that the inner diameter of the portion located on the fixed sliding ring 6 side from the step portion 40d of the inner cylinder portion 40c of the cartridge 40. The diameter of the portion 40c is smaller than the inner diameter of the portion located on the side opposite to the stationary sliding ring 6 from the step portion 40d. That is, the metal bellows 30 has a shape in which the inner diameter side is stepped in a sectional view.
Hereinafter, for convenience of explanation, a portion having a large inner diameter of the bellows 30 may be referred to as a large inner diameter portion 30-1, and a portion having a small inner diameter may be referred to as a small inner diameter portion 30-2.

Since the effective diameter of the large inner diameter portion 30-1 of the bellows 30 is the same as that of the reference example, the pressure receiving area A1-1 represented by the area between the effective diameter and the outer diameter of the sliding surface S is small. The balance value is also reduced.
On the other hand, since the effective diameter of the small inner diameter portion 30-2 of the bellows 30 is smaller than that of the large inner diameter portion 30-1, the pressure receiving area A1 represented by the area between the effective diameter and the outer diameter of the sliding surface S. -2 is large and the balance value is also large.
For this reason, the overall balance value of the bellows 30 is larger than the balance value of the bellows having the same outer diameter shown in FIG. 9 and not stepped (reference example), and suppresses a decrease in the balance value. The amount of leakage of the sliding surface S can be reduced. Moreover, the increase in the spring constant of the bellows 30 can be suppressed.

  In the present embodiment, the distal end 20d of the inner cylindrical portion 20 of the sleeve 20 is expanded by caulking and engaged with the inner cylindrical portion 40c of the cartridge 40, thereby preventing the cartridge 40 and the sleeve 20 from coming off in the axial direction. In this type, the inner cylinder portion 40c of the cartridge 40 is provided with a stepped portion 40d in which the diameter of the portion located on the opposite side to the fixed sliding ring 6 side is increased, and the bellows 30 is provided with the inner cylinder portion of the cartridge 40. Since the inner diameter of the portion located on the fixed sliding ring 6 side from the step 40d of the portion 40c is smaller than the inner diameter of the portion located on the opposite side of the fixed sliding ring 6 from the step 40d, the bellows Compared with the case where the outer diameter is the same and the inner diameter is increased uniformly, the balance value is increased, the decrease of the balance value can be suppressed, and the leakage amount of the sliding surface S can be reduced. . Moreover, the increase in the spring constant of the bellows 30 can be suppressed. In other words, the decrease in the balance value can be suppressed without increasing the outer diameter of the bellows, the leakage amount of the sliding surface S can be reduced, and the increase in the spring constant of the bellows 30 can be suppressed. It has a remarkable effect that it can be performed.

Next, a mechanical seal according to Embodiment 6 of the present invention will be described with reference to FIG.
The sixth embodiment shown in FIG. 6 is the same as the fifth embodiment shown in FIG. 5 in that the cartridge and the sleeve can be prevented from detaching in the axial direction and are integrated by so-called fixed / rotating side caulking. There is a difference from the fifth embodiment shown in FIG. 5 in that the balance value is set to exceed 100%.
In the following, overlapping description of the same points as in the fifth embodiment will be omitted.

  In the case of Example 6 shown in FIG. 6, the pressure receiving area received from the sealed fluid of the metal bellows 30 is A1 (the average value of the pressure receiving area A1-1 and the pressure receiving area A1-1), and the rotation side sliding ring 5 When the sliding area between the fixed side sliding ring 6 and A2 is A2, the balance value represented by the ratio of A1 / A2 is set to exceed 100%.

In order to set the balance value to exceed 100%, it is necessary to make the inner diameter of the sliding surface of the rotating side sliding ring 5 and the fixed side sliding ring 6 larger than the balance diameter (effective diameter) of the bellows 30. Therefore, if the balance diameter of the bellows 30 is constant, the diameters of the rotation-side sliding ring 5 and the stationary-side sliding ring 6 are increased, and there is a problem that the mechanical seal is increased in size.
According to the sixth embodiment, since the small inner diameter portion 30-2 of the bellows 30 has an effective diameter smaller than that of the large inner diameter portion 30-1, sliding between the rotating side sliding ring 5 and the fixed side sliding ring 6 is performed. An increase in the inner diameter of the surface can be suppressed.

In the present embodiment, the distal end 20d of the inner cylindrical portion 20 of the sleeve 20 is expanded by caulking and engaged with the inner cylindrical portion 40c of the cartridge 40, thereby preventing the cartridge 40 and the sleeve 20 from coming off in the axial direction. In this type, the inner cylinder portion 40c of the cartridge 40 is provided with a stepped portion 40d in which the diameter of the portion located on the opposite side to the fixed sliding ring 6 side is increased, and the bellows 30 is provided with the inner cylinder portion of the cartridge 40. Since the inner diameter of the portion located on the fixed sliding ring 6 side from the step 40d of the portion 40c is smaller than the inner diameter of the portion located on the opposite side of the fixed sliding ring 6 from the step 40d, the bellows Even when the balance value is set to exceed 100% compared to the case where the outer diameter is the same and the inner diameter is uniformly increased, the rotation-side sliding ring 5 and the stationary-side sliding ring 6 Sliding surface It is possible to suppress the increase in diameter of the diameter.
In other words, the balance value can be set to exceed 100% without greatly increasing the diameters of the rotation-side sliding ring 5 and the stationary-side sliding ring 6, and the enlargement of the mechanical seal is avoided. There is a remarkable effect that it is possible.

  As described above, the embodiments of the present invention have been described based on the examples. However, the specific configuration is not limited to these examples, and changes and additions may be made without departing from the scope of the present invention. It is included in the present invention.

  For example, in the above-described embodiment, the case where the mechanical seal of the present invention is applied to a pump has been described. However, the present invention is not limited thereto, and can be applied to various industrial machines such as a compressor and a submersible motor.

  For example, in the above-described embodiment, the case where the cartridge 4 and the case 8 are made of metal is described. However, the material is not limited to metal, and may be any material having high corrosion resistance, and may be made of plastic, for example. In this case, the fixing with the metal bellows may be, for example, bonding with an adhesive or bonding with a laser.

Further, for example, in the first to fifth embodiments, a case where the balance value is set in a range of 50% ≦ balance value ≦ 100% will be described, and in the sixth embodiment, the balance value is set to exceed 100%. As described above, the present invention is applicable to any balance value.
The balance value is appropriately set according to the type of sealed fluid, pressure, and the like.

  In addition, for example, in Examples 5 and 6 described above, the effect of the present invention has been described by taking the case where the outer diameter of the bellows is the same for convenience of explanation, but the present invention is not limited thereto. Even if the outer diameter of the bellows 30 varies, the present invention is effective. In short, in a type in which the fixed side and the rotating side are integrated, by reducing the inner diameter of a part of the bellows 30, it is possible to prevent a decrease in the balance value or to prevent the rotating ring and the fixed ring from increasing in diameter. In particular, it has technical significance.

  That is, when the balance value is in the range of 50% ≦ balance value ≦ 100% as in the fifth embodiment, a decrease in the balance value is prevented, and when the balance value exceeds 100% as in the sixth embodiment. The increase in the diameters of the rotation-side sliding ring and the stationary-side sliding ring is suppressed, and the increase in the size of the mechanical seal is avoided.

DESCRIPTION OF SYMBOLS 1 Rotating shaft 2 Sleeve 3 Housing 4 Cartridge 5 Rotating side sliding ring 6 Fixed side sliding ring 7 Metal bellows 8 Case 9 Cup gasket 10 Cup gasket 15 Metal bellows
16 Band 20 Sleeve 30 Metal bellows 40 Cartridge

Claims (4)

A sleeve fixed to the rotary shaft; and a cartridge fixed to the housing. The sleeve is provided with a rotation-side sliding ring, and the cartridge is fixed to slide against the rotation-side sliding ring. In the inside type mechanical seal provided with a side sliding ring and a bellows for urging the fixed side sliding ring in the axial direction, the bellows is made of metal, and one end of the metal bellows is fixed side It is fixed to the case holding the sliding ring, the other end is fixed to the cartridge, and the plate thickness is set to be thinner than the plate thickness of the case or the cartridge ,
The metal bellows includes a bellows portion in which peaks and valleys are alternately and repeatedly formed, and disk-shaped flange portions extending radially outward from the valley portions at both ends of the bellows portion, and the flange portion The mechanical seal is formed by molding or welding so that the outer diameter of the flange portion is larger than the diameter of the peak portion, and the inner diameter of the flange portion is substantially the same as or slightly larger than the diameter of the valley portion. . The fixing of the metal bellows to the metal case and the metal cartridge is performed by welding or welding at a position slightly inside the outer diameter of the flange portion of the metal bellows. The mechanical seal according to claim 1 . Claim 1, wherein the rotating-side slide ring is fixed via a cup gasket into the sleeve, the cup gasket and which are located across the counter-sliding surface side and the outer peripheral surface of the rotary side sliding ring Or the mechanical seal of 2 . The inner cylinder of the cartridge is of a type in which the tip of the inner cylinder of the sleeve is expanded by caulking and engaged with the inner cylinder of the cartridge to prevent the cartridge and the sleeve from coming off in the axial direction. The part is provided with a stepped portion having an enlarged diameter located on the side opposite to the fixed sliding ring side, and the bellows extends from the stepped part of the inner cylindrical portion of the cartridge to the fixed sliding ring side. claims 1, characterized in that the inner diameter portion is formed smaller in diameter than the inner diameter of the portion located on the opposite side to the fixed side sliding ring from the stepped portion of the inner cylindrical portion of the cartridge located in any of the 3 The mechanical seal according to claim 1.

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